Drill pipe float valves



Oct. 16, 1962 J. D. KEITHAHN DRILL PIPE FLOAT VALVES Filed April 29, 1958 2 Sheets-Sheet 1 BY m Oct. 16, 1962 Filed April 29, 1958 J. D. KEITHAHN DRILL PIPE FLOAT VALVES 2 Sheets-Sheet 2 JULIAN D. KEITHAHN INVENTOR.

United States Patent Oflflce 3,5,53d Patented Oct. 16, 1962 3,058,534 DL PIPE FLOAT VALVE Julian D. Keithahn, Anaheim, Calif., assignor to Baker Oil Tools, Inc. Los Angeies, Calif., a corporation of California Filed Apr. 29, 1953, Ser. No. 731,732 6 Claims. (Cl. 17s 31s The present invention relates to subsurface well bore equipment, and more particularly to drill pipe float valves used in strings of drill pipe during the drilling of the well bore.

A drill pipe float valve is incorporated in a rotary string of drill pipe, usually near the drill bit, to relieve the weight on the derrick and rig equipment during lowering of the drilling string through the fluid in the well bore, to reduce the chance of plugging the drill bit, to prevent blow-outs, to prevent wetting of the rig floor and equipment, to minimize damage in the event the drilling string should part, and to accomplish other known purposes. A drill pipe float valve is essentially a back pressure valve which opens in a downward direction to allow drilling mud and the like to be pumped down through the drill pipe for discharge from the bit, but which closes in an upward direction to prevent reverse or upward flow of the drilling mud in the drill pipe.

Heretofore, drill pipe float valves have been subjected to the erosive wear of the drilling mud being pumped through them, which has resulted in fluid cutting of the parts and a consequent shortening in their useful life. Such erosive wear has occurred not only upon the metallic members of the valves, but also on the rubber or rubberlike sealing elements, which, at times, have been washed out of their assembled location on the valve apparatus. The valves have also leaked, which is believed to be due to improper seating of the valve head against its companion valve seat. Failure of certain valve parts has also occurred from other causes. One of such causes is thought to be due to vibration imparted by the drill bit to the drilling string as the cutter teeth of the drill bit roll around on the bottom of the well bore.

An object of the present invention is to provide a drill pipe float valve which has a substantially full opening therethrough when drilling mud is being pumped down through the drilling string, thereby minimizing erosive wear on the valve parts and increasing the useful life of the valve.

Another object of the invention is to provide a drill pipe float valve in which proper seating of the valve head against its companion valve seat is assured.

A further object of the invention is to provide a drill pipe float valve in which the rubber or rubber-like sealing element is protected from the direct action of the drilling fluid, preventing such fluid from washing out the element from its appropriate assembled position in the valve and from fluid cutting the element.

Yet another object of the invention is to provide a simple manner of retaining in place the rubber or rubberlike sealing element of a drill pipe float valve.

An additional object of the invention is to prevent the vibration imparted by a rotary drilling bit to a drill pipe float valve from damaging its parts.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of several forms in which it may be embodied. Such forms are shown in the drawings ac companying and forming part of the present specification. These forms will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a longitudinal section through a drill pipe float valve disposed in a string of drill pipe, the valve being in closed position;

FIG. 2 is a cross-section taken along the line 22 on FIG. 1;

FIG. 3 is a longitudinal section through the hinge pin portion of the float valve;

FIG. 4 is a longitudinal section through another embodiment of the invention;

FIG. 5 is a cross-section taken along the line 55 on FIG. 4.

In the form of invention illustrated in FIGS. 1, 2 and 3, a drill pipe float valve A is placed within a string of drill pipe, such as within a counterbore 10 of a drill collar B, the upper end of the counterbore providing a stop shoulder 11 against which the valve body or cage 12 can bear. The lower end of the drill collar may be constituted as a threaded box 13 adapted to be threadedly secured to a threaded pin 14 of an adjacent drill pipe section or the drill bit C. The upper end 15 of the pin forms a lower stop shoulder for preventing downward movement of the valve cage or body 12.

The valve cage or body includes an upper portion 16 having a central passage 17 therethrough, the upper end of this upper portion being adapted to engage the upper stop shoulder 11. It also includes a lower portion 18 adapted to rest upon the lower stop shoulder 15, and also having a large diameter central passage 19 therethrough. These two portions 16, 18 are held in spaced relation longitudinally from one another by a plurality, such as a pair, of diametrically opposite legs 2% which are preferably integral with both of the portions.

Leakage of fluid around the upper body portion 16 and the wall of the counterbore 10 in both longitudinal directions is prevented by upper and lower oppositely facing side seal rings 21, 22. Thus, the upper seal ring 21 includes a base portion 23 fitting within a peripheral groove 24 in the body, there being an upwardly directed lip portion 25 adapted to sealingly engage the wall of the counterbore. The lower seal ring 22 includes a base portion 26 fitting within a peripheral groove 27 in the body of the tool and having a downwardly extending lip portion 28 sealing against the wall of the counterbore 10. The valve cage 12 is slipped up into the counterbore 10 prior to attachment of the lower pipe section C to the drill pipe or collar B, the lower member C then being threaded into the box 13 to hold the valve cage in proper position within the drill collar, with the upper and lower seals 21, 22 preventing passage of fluid around the upper portion 16 of the valve body in both longitudinal directions.

The lower end of the upper body portion 16 is constituted as a valve seat 29 having a gasket type of rubber or rubber-like sealing element 30 secured therewithin and preferably projecting below the lower metallic face of the valve seat. The rubber or rubber-like seal ring 30 is secured to the upper valve body portion by virtue of an outwardly directed upper flange 31 of the ring fitting within a companion internal circumferential groove 32 in the valve body. The seal ring 30 is protected from the action of the fluid that may be pumped down through the valve apparatus by a retainer sleeve 33 which fits within a counterbore 34 in the valve body, the upper end of the sleeve abutting a shoulder 35 provided by the upper end of the counterbore and the lower end of the sleeve terminating substantially in the same transverse plane as the lower face 29 of the upper valve body portion. This sleeve 33 makes a press fit within the valve body 12 and also fits across the inner surface of the seal ring except for the lower end of the latter projecting below the lower end of the retainer sleeve 33. The inside diameter of the retainer sleeve is substantially the same as the inside di ameter of the body passage 17 immediately thereabove, so as to provide a smooth, continuous passage through the upper valve body portion 16.

The valve is closed against upward passage of fluid whenever a valve head member 36 swings upwardly into engagement with the lower end of the seal ring 30, as disclosed in FIG. 1. This valve head includes an inner portion 37 of disc shape having its upper face 38 adapted to engage the lower end of the seal ring 30. The inner portion 37 has a threaded stem 39' threadedly received within an arm 40 of the valve head, which is pivotally supported at one side of the valve body 12. To insure against inadvertent unscrewing of the inner valve head portion 38 from its arm portion 40, a set screw 41 may be threaded in the arm and tightened against the inner head portion.

The arm portion 40 extends to the side of the body, the outer parts 42, 42 of the arm being bifurcated and being disposed between depending bearings or ears 43 that are integral with the upper valve cage body portion 16. A hinge pin 44 extends through aligned holes or bores 45 in the bifurcations 42 and also through aligned bores 46 in the ears or bearings 43, thereby providing a pivotal support for the valve head 36 to one side of the valve body 12, whereby the valve head can swing downwardly to one side of the valve body and substantially completely out of the path of the fluid being pumped down through the apparatus, to provide a full opening through the apparatus. Downward movement of the valve head 36 is limited by engagement of the arm 40 with an upper stop 47 on the lower valve body portion 18 below the ears 43. The valve head is urged in an upward direction by a spring 48 which includes an intermediate coil portion 49 encircling the hinge pin 44, there being one arm 50 of the spring received within a slot 51 in the valve body 12 and bearing against the latter, and another arm 52 of the spring extending from the coil portion 49 and engaging the valve head 36 to urge it in an upward direction. The spring 48 is disposed between the bifurcations 42 of the arm 40 and its coil portion 49 may have a diameter substantially greater than the diameter of the hinge pin 44.

The hinge pin 44 includes a metallic central or core portion 55 that has a pliant, elastic cover 56 thereon, such as a rubber or a rubber-like covering. This cover 56 has a substantial thickness. As an example, its thickness may be of the order of of an inch. The rubber thickness is such that the overall diameter of the pin conforms to the diameters of the bores 45, 46 through the bifurcations 42 and the bearing cars 43. However, it is found that it is not necessary for a snug fit to be secured. In fact, the valve head 36 may pivot on the pin 44 and may also turn or rotate within the bearings 43.

In the use of the apparatus described, the valve head 36 will engage the sealing element 30 and prevent up ward flow of fluid through the string of drill pipe. However, when the drilling mud or other fluid is pumped down through the drill pipe, it will swing the flapper valve head 36 against the force of the spring 48 to its full open position against the stop 47, there then being a very large bore or passage through the apparatus through which the drilling fluid can flow in an unimpeded manner and into the drill pipe or drill bit therebelow. During the downward pumping of the fluid, it will not move along the rubber sealing element 30, since the latter is protected by the retainer sleeve 33. The absence of direct impinging of the drilling fluid on the seal element also prevents the latter from being inadvertently washed out of its assembled position on the upper valve body portion 16.

While the rotary drilling action is taking place and the drilling mud is being pumped down through the drilling string and the valve apparatus A contained therewithin, the rolling of the drill bit teeth on the bottom of the hole sets up vibrations in the drill string and in the valve apparatus itself. Such vibrations do not cause the valve head 36 to pound upon the hinge pin 44 and wear the latter or cause its failure, as well as possible failure of the valve head arm itself. The rubber 56, which is interposed between the valve head 36 and the hinge pin and also between the hinge pin and the bearings 43 acts as an effective shock absorber or vibration damper, completely eliminating any hammering action on the parts that could cause their failure While the apparatus is in use in the well bore.

In the absence of the drilling fluid being pumped down through the apparatus, the valve head 36 will swing up wardly into engagement with its companion rubber seat 30. Proper seating is insured since the intervention of the pliant material 56 between the valve head arm 40 and the hinge pin 55 and also the intervention of the rubber material between the hinge pin and the bearing ears 43 permits the valve head to have a suflicient freedom or universality of movement in substantially all directions so that it adjusts itself safely and insures a flat and proper contact of the valve head surface 38 against the seal ring 38 around the complete circumference of the coengaging parts. In the absence of the intervening rubber or cushioning material 56, the valve head could only swing about the axis of the hinge pin and the proper flat engagement of the valve head surface 38 against the sealing ring 30 might not occur, introducing an area of leaking that could increase as fluid passes therethrough, particularly during the lowering of the drill pipe apparatus in the well bore and at substantial depths, in which the hydrostatic head of fluid acting upon the valve apparatus is very substantial and of the order of several thousand pounds per square inch.

In the form of invention illustrated in FIGS. 4 and 5, provision is made for insuring the proper seating of the valve head against the seal ring 30, which is secured in the upper valve body or cage portion by the retainer sleeve 33. In lieu of the intervening rubber material in the other form of the invention, the arm 40a is mounted upon a metallic hinge pin 44a passing through aligned bores 45a in the arm bifurcations 42a. A snug fit of the pin in these arms may be provided. The pin also extends into the aligned bores 46a in the body ears 43, and may also make a snug fit therewithin. The inner valve head portion 37a is not rigidly secured to the valve arm 40a, but is mounted thereon to partake of a slight pivotal motion with respectthereto. Thus, the inner valve head portion has a central lug or boss 60 extending downwardly between inner bifurcations 61 of the valve arm. A hinge pin 62 extends through aligned bores 63 in the inner bifurcations and through a bore 64 in the boss. A set screw 65, or the like, may be threaded in the boss 60 and tightened against the hinge pin 62 to prevent relative movement between the parts. Slight free swinging between the inner valve head portion 37a and the valve head arm portion 40a is permitted by a spring 66 having a central coil portion 67 disposed around the hinge pin 62 outside of one of the bifurcated arms 61, one arm 68 of the spring bearing against the arm 61 and another arm 69 of the spring bearing against the valve head portion 37a.

During the use of the apparatus in a string of drill pipe, the pumping of drilling mud down through the valve apparatus will displace the valve head member 37a, 40a downwardly to swing them around the outer hinge pin axis, and against the force of the spring 48 completely to one side of the valve body 12, so that fluid can flow through the bore of the apparatus in an unrestricted fashion into the drill pipe C therebelow. Upon cessation of the downward pumping of the fluid, the spring 48 will swing the valve head about the hinge pin axis up toward the seat 30, bringing the upper face 38 of the valve head against the seal ring. The valve head member 37a can pivot about the axis of the inner hinge 62 and with respect to the valve head arm 40a, to better accommodate itself to the seal ring 30 and insure a flat seating engagement of the valve head surface 38 against the seal ring around the full circumference of these parts.

I claim:

1. In apparatus of the character described: a rotary drilling string for drilling a bore hole and extending downwardly from the top of the ground; a rotary drill bit secured to the lower portion of said drilling string and having toothed roller cutters for drilling the hole; a valve body in said drilling string having a passage therethrough surrounded by a valve seat and through which fluid pumped down the drilling string can flow; a valve head movable upwardly into engagement with said seat; and means mounting said head for pivotal movement to and from engagement with said seat, said means including a pivot pin, and pliant, elastic material between said head and pivot pin.

2. In apparatus of the character described: a rotary drilling string for drilling a bore hole and extending downwardly from the top of the ground; a rotary drill bit secured to the lower portion of said drilling string and having toothed roller cutters for drilling the hole; a valve body in said drilling string having a passage therethrough surrounded by a valve seat and through which fluid pumped down the drilling string can flow; a Valve head movable upwardly into engagement with said seat; and means mounting said head on said body for pivotal movement to and from engagement with said seat, said means including a pivot pin carrying said head, and pliant, elastic material between said pin and body.

3. In apparatus of the character described: a rotary drilling string for drilling a bore hole and extending downwardly from the top of the ground; a rotary drill bit secured to the lower portion of said drilling string and having toothed roller cutters for drilling the hole; a valve body in said drilling string having a passage therethrough surrounded by a valve seat and through which fluid pumped down the drilling string can flow; a valve head movable upwardly into engagement with said seat; and means mounting said head on said body for pivotal movement to and from engagement with said seat, said means including a pivot pin, pliant, elastic material between said head and pin, and pliant, elastic material between said pin and body.

4. In apparatus of the character described: a rotary drilling string for drilling a bore hole and extending downwardly from the top of the ground; a rotary drill bit secured to the lower portion of said drilling string and having toothed roller cutters for drilling the hole; a valve body in said drilling string having a passage therethrough surrounded by a valve seat and through which fluid pumped down the drilling string can flow; a valve head movable upwardly into engagement With said seat; and means mounting said head on said body for pivotal movement to and from engagement with said seat, said means including a pivot pin extending into said body and head, and a pliant, elastic cover on said pin bearing against said body and head.

5. In apparatus of the character described: a rotary drilling string for drilling a bore hole and extending downwardly from the top of the ground; a valve body in said drilling string having a passage therethrough surrounded by an end face providing a valve seat and through which fluid pumped down the drilling string can flow; a pliant, elastic seal ring mounted on said body and extending to said end face; said body having a counterbore adjacent to said seal ring; an annular retainer disposed in said counterbore and covering the inner surface of said seal ring, the inner surface of said retainer constituting a continuation of said passage; a valve head movable upwardly into engagement with said seal ring and seat; and means mounting said head for pivotal movement to and from engagement with said seat, said means including a pivot pin, and pliant, elastic material between said head and pivot pin.

6. In apparatus of the character described: a rotary drilling string for drilling a bore hole and extending downwardly from the top of the ground; a valve body in said drilling string having a passage therethrough surrounded by an end face providing a valve seat and through which fluid pumped down the drilling string can flow; a pliant, elastic seal ring mounted on said body and extending to said end face; said body having a counterbore adjacent to said seal ring; an annular retainer disposed in said counterbore and covering the inner surface of said seal ring, the inner surface of said retainer constituting a continuation of said passage; a valve head movable upwardly into engagement with said seal ring and seat; and means mounting said head for pivotal movement to and from engagement with said seat, said means including a pivot pin extending into said body and head, and a pliant, elastic cover on said pin bearing against said body and head.

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